Exhaust for steam-turbines.



G. V. KERR. EXHAU ST FOR STEAM TURBINBS.

APPLICATION FILED FEB. 7,1914

Patented Maw, 1915;

mansions GHABLES V0141? EY KERR, 3F ELLS? Lil 1E, "1 03K.

FOR. STEAM-TUHBINES.

Specification. of Letters Patent.-

l atented Mar, 9., til

Application filed February 7,. 191 Serial no.

back pressure of the. turbine. Secondz'to so arrange and construct theexhaust pasa turbiuc,.that the residual velocity remaining in theexhaust steam after leaving the last bucket or vane can be utilized toincrease the exhaustpressure, instead of Wasting it in needless andobstructing eddies, and therehy e'fiect a lower pressure the exhaust endof the turbine casing than in the connected exhaust pipe or chamber,heretofore used. Third: to so construct and arrange theexhaust passageof the turbine, that the residual velocity'remaining in the exhauststeam is utilized uniformly around and at all the buckets of the lastbucket Wheel or rotor, therehy'providing a uniform pressure anddischarge of fluid pressure at the periphery of the last bucket Wheel,at the dill'erent stages of expansion throughoutthc turbine. Fourth:other objects and advantages of the invention Will appear "from thedtailed description which will he hereinafter more fully given.

The invention consists of structural features relative arrangementsofthe elements of the inveution, which-will be hereinafter more fully?described and. particularly pointed out in the appended claims.

In the drawings, in Which similar reference characters indicate the sameparts in the several fi ures of drawing; Figure 1 is a longitudinalscctionon'line lll of'Fig. 22, of the exhaust end of a turbine with theimproved volute exhaust passage attached thereto; and Fig. 2 is atransverse section on line l1-ll of Fig. 1.

Referring to Fig. 1 of the drawingspln which the et'rhaust' end of aturbine is rep resented, 1 is a rotary shaft to which is sccured'in anysuitable manner two rotary Wheels 2, 3,-having buckets 2, and 3",

' volute shapedenh A cap carry respectively, on their peripheries. 4 isa section of the rhino casing provided with the stationary nozzles forguiding the steam into the buckets 2, and is a ring having stationaryreversing nozzles 7, to r eteive the steam. from the bucletets 2 on therotary wheel end guide the sameinto thebuclrets 3 on the rotary Wheel 3.Said sections or rings s, and 6, are preferably independent of eachother and are dovetailed at their oints,

and fornrno essential part of the present 1 invention, as anypther formor type or thr bine may be used ,;b'ut"'are illustrated in the presentinstance for the purpose ofsho'wing the constructlon and ndication ofthe i331:

1 proved exhaust passages with .a turbine.

'lhe exhaust end of "theflstesan' turbine is .ciosed by a need.8,-prov1ded with theiin proved exha'r passage preferably therein, saiaustpassagc being provided With an exha nozzle 9 having its smallerannular opening the inner side of the head 8 adjacent to and incommunication with the final exhaust irorh the turbine buckets, orexhaust ends of the series of s on the last rotary Wheel or hucke',rotor 3, as shown in l. annular exhaust nozzle 9 esp-ands outwardly andopens into an. exhaust passage 10, of, in creasing cross-sectional areaand or" volute shape, said passage 10 having an outlet or discharge 11which is connected to the usual exhaust pipe leadim to the atmosphere orThe bottom of the passage 1G is prolghavinga valve,

condenser, o. sire-3. volute shaped exhaust ""lCl Ql with o not shown,to drainauy Water of condensa-' tron, or oil, which may collect. at thispoint. The head. 8 is proviced with an opening centrally disposed withrespect to the rust passa e 10 and annular nozzle fo the passage of theshaft 1,. 111g he usual stufiing box 15 with packing glands, anda'hearing 16,.as shown, is firmly secured over the opening 13, and needsno further disclosure, as it forms no essential feature of the presentinvention.

The operation ofthe invention is as follows: The steam havingheenadmitted into the inlet of the turbine, it passes through' o e or morestages, andlinally reaches the last stage, and then passes with aresidual velocity from the exlihustvside of the last scriesfoi bucketsor vanes 3 3, on the wheel LLO v against the .Walls of the voluteexhaust passage 10, to form interfering eddies 1r needless frictionagainst the walls of the exhaust passage.

The residual velocity in the annular nozzle 9, and the whirling actionwithin the volute exhaust passage 10 results in a decrease of velocityand an increase of density in the steam issuing from the buckets 3', 3,and an increase in pressure of the exhaust steam.

'This means, for example, if the turbine eX- hausts against atmosphericpressure, the steam may expand in the turbine until the pressure in thelast stage is somewhat less than atmospheric pressure. Or, if theexhaust is into a 'acuum, the pressure in the last stage may be as lowas in the condenser, since the decrease in velocity of exhaust maybalance the pressureacquired to overcome friction in piping between theturbine and condenser.

hat i claim is 1. A steam turbine comprising a cylinder, a rotatableshaft, bucket .wheels rotating with said shaft, a volutc exhaust passagehaving an'outlet and an annular inlet and of gradually increasingcross-sectional area from its inlet to its outlet, and an annularunobstructed nozzle having sections in planes passing through the axisof the shaft in the form of a diverging nozzle, the inlet of saidannular nozzle being placed'at the discharge side of the buckets on theWheel adjacent to the exhaust and the curvature of the outlet of theannular nozzle merging smoothly into the curvature of the annular inletof the volute exhaustpassage.

' 2. A steam turbine comprising a cylinder, a rotatable shaft, bucketwheels rotating with said shaft, a volute exhaust passage having anoutlet and an annular inlet, and Y an annular nozzle having sections inplanes passingthrough the axis of the shaft in the form of a divergingnozzle, the inlet of said annular nozzle being placed at the dischargeside of the buckets on the wheel adjacent to the exhaust and the outletof the annular nozzle merging smoothly in the annular inlet of theexhaust passage, and said exhaust passage rranged so that exhaust steamfrom said buckets of said Wheel flows around the exhaust passage andissues from said outlet in a direction backward to the direction ofrotation of the said bucket wheel.

In testimony whereof I aifix my signature in presence of two Witnesses.

GHARLESC VOLNEY KERR. Witnesses (J. \V. GREENFIEL M. E. RISING.

